[PATCH v4 1/2] dt-bindings:iio:adc: add max14001

[PATCH v4 1/2] dt-bindings:iio:adc: add max14001

[Kim Seer Paller]

The MAX14001 is a configurable, isolated 10-bit ADC for multi-range 
binary inputs.

Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
V3 -> V4: Added space between prefixes in commit description.

 .../bindings/iio/adc/adi,max14001.yaml        | 54 +++++++++++++++++++
 MAINTAINERS                                   |  7 +++
 2 files changed, 61 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml b/Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
new file mode 100644
index 000000000000..9d03c611fca3
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2023 Analog Devices Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,max14001.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices MAX14001 ADC
+
+maintainers:
+  - Kim Seer Paller <kimseer.paller@analog.com>
+
+description: |
+    Single channel 10 bit ADC with SPI interface. Datasheet
+    can be found here:
+      https://www.analog.com/media/en/technical-documentation/data-sheets/MAX14001-MAX14002.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,max14001
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 5000000
+
+  vref-supply:
+    description: Voltage reference to establish input scaling.
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+            compatible = "adi,max14001";
+            reg = <0>;
+            spi-max-frequency = <5000000>;
+            vref-supply = <&vref_reg>;
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index f794002a192e..7e009d12d0d9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12670,6 +12670,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/sound/max9860.txt
 F:	sound/soc/codecs/max9860.*
 
+MAX14001 IIO ADC DRIVER
+M:	Kim Seer Paller <kimseer.paller@analog.com>
+L:	linux-iio@vger.kernel.org
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/iio/dac/adi,max14001.yaml
+
 MAXBOTIX ULTRASONIC RANGER IIO DRIVER
 M:	Andreas Klinger <ak@it-klinger.de>
 L:	linux-iio@vger.kernel.org

base-commit: 6f449d52b90fdd927fcf9df0388701de6d5381c6
-- 
2.34.1

[PATCH v4 2/2] iio: adc: max14001: New driver

[Kim Seer Paller]

The MAX14001 is a configurable, isolated 10-bit ADC for multi-range 
binary inputs.

Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
---
V3 -> V4: Removed regmap setup, structures, and include.

 MAINTAINERS                |   1 +
 drivers/iio/adc/Kconfig    |  10 ++
 drivers/iio/adc/Makefile   |   1 +
 drivers/iio/adc/max14001.c | 328 +++++++++++++++++++++++++++++++++++++
 4 files changed, 340 insertions(+)
 create mode 100644 drivers/iio/adc/max14001.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 7e009d12d0d9..88aa91fd7494 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12676,6 +12676,7 @@ L:	linux-iio@vger.kernel.org
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/dac/adi,max14001.yaml
+F:	drivers/iio/adc/max14001.c
 
 MAXBOTIX ULTRASONIC RANGER IIO DRIVER
 M:	Andreas Klinger <ak@it-klinger.de>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index eb2b09ef5d5b..e599d166e98d 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -706,6 +706,16 @@ config MAX11410
 	  To compile this driver as a module, choose M here: the module will be
 	  called max11410.
 
+config MAX14001
+	tristate "Analog Devices MAX14001 ADC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices MAX14001 Configurable,
+	  Isolated 10-bit ADCs for Multi-Range Binary Inputs.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called max14001.
+
 config MAX1241
 	tristate "Maxim max1241 ADC driver"
 	depends on SPI_MASTER
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index e07e4a3e6237..9f8964258f03 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_MAX11100) += max11100.o
 obj-$(CONFIG_MAX1118) += max1118.o
 obj-$(CONFIG_MAX11205) += max11205.o
 obj-$(CONFIG_MAX11410) += max11410.o
+obj-$(CONFIG_MAX14001) += max14001.o
 obj-$(CONFIG_MAX1241) += max1241.o
 obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MAX9611) += max9611.o
diff --git a/drivers/iio/adc/max14001.c b/drivers/iio/adc/max14001.c
new file mode 100644
index 000000000000..bbee7454dbee
--- /dev/null
+++ b/drivers/iio/adc/max14001.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+/*
+ * Analog Devices MAX14001 ADC driver
+ *
+ * Copyright 2023 Analog Devices Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitrev.h>
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <asm/unaligned.h>
+
+/* MAX14001 Registers Address */
+#define MAX14001_ADC			0x00
+#define MAX14001_FADC			0x01
+#define MAX14001_FLAGS			0x02
+#define MAX14001_FLTEN			0x03
+#define MAX14001_THL			0x04
+#define MAX14001_THU			0x05
+#define MAX14001_INRR			0x06
+#define MAX14001_INRT			0x07
+#define MAX14001_INRP			0x08
+#define MAX14001_CFG			0x09
+#define MAX14001_ENBL			0x0A
+#define MAX14001_ACT			0x0B
+#define MAX14001_WEN			0x0C
+
+#define MAX14001_VERIFICATION_REG(x)	((x) + 0x10)
+
+#define MAX14001_CFG_EXRF		BIT(5)
+
+#define MAX14001_ADDR_MASK		GENMASK(15, 11)
+#define MAX14001_DATA_MASK		GENMASK(9, 0)
+#define MAX14001_FILTER_MASK		GENMASK(3, 2)
+
+#define MAX14001_SET_WRITE_BIT		BIT(10)
+#define MAX14001_WRITE_WEN		0x294
+
+struct max14001_state {
+	struct spi_device	*spi;
+	/*
+	 * lock protect agains multiple concurrent accesses, RMW sequence, and
+	 * SPI transfer
+	 */
+	struct mutex		lock;
+	int			vref_mv;
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	__be16			spi_tx_buffer __aligned(IIO_DMA_MINALIGN);
+	__be16			spi_rx_buffer;
+};
+
+static int max14001_read(void *context, unsigned int reg_addr, unsigned int *data)
+{
+	struct max14001_state *st = context;
+	int ret;
+
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = &st->spi_tx_buffer,
+			.len = 2,
+			.cs_change = 1,
+		}, {
+			.rx_buf = &st->spi_rx_buffer,
+			.len = 2,
+		},
+	};
+
+	st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK,
+								reg_addr)));
+
+	ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
+	if (ret)
+		return ret;
+
+	*data = bitrev16(be16_to_cpu(st->spi_rx_buffer)) & MAX14001_DATA_MASK;
+
+	return 0;
+}
+
+static int max14001_write(void *context, unsigned int reg_addr, unsigned int data)
+{
+	struct max14001_state *st = context;
+
+	st->spi_tx_buffer = bitrev16(cpu_to_be16(
+			FIELD_PREP(MAX14001_ADDR_MASK, reg_addr) |
+			FIELD_PREP(MAX14001_SET_WRITE_BIT, 1) |
+			FIELD_PREP(MAX14001_DATA_MASK, data)));
+
+	return spi_write(st->spi, &st->spi_tx_buffer, sizeof(st->spi_tx_buffer));
+}
+
+static int max14001_write_verification_reg(struct max14001_state *st,
+						unsigned int reg_addr)
+{
+	unsigned int reg_data;
+	int ret;
+
+	ret = max14001_read(st, reg_addr, &reg_data);
+	if (ret)
+		return ret;
+
+	return max14001_write(st, MAX14001_VERIFICATION_REG(reg_addr), reg_data);
+}
+
+static int max14001_reg_update(struct max14001_state *st,
+				unsigned int reg_addr,
+				unsigned int mask,
+				unsigned int val)
+{
+	int ret;
+	unsigned int reg_data;
+
+	/* Enable SPI Registers Write */
+	ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN);
+	if (ret)
+		return ret;
+
+	ret = max14001_read(st, reg_addr, &reg_data);
+	if (ret)
+		return ret;
+
+	reg_data = FIELD_PREP(mask, val);
+
+	ret = max14001_write(st, reg_addr, reg_data);
+	if (ret)
+		return ret;
+
+	/* Write Verification Register */
+	ret = max14001_write_verification_reg(st, reg_addr);
+	if (ret)
+		return ret;
+
+	/* Disable SPI Registers Write */
+	return max14001_write(st, MAX14001_WEN, 0);
+}
+
+static int max14001_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct max14001_state *st = iio_priv(indio_dev);
+	unsigned int data;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&st->lock);
+		ret = max14001_read(st, MAX14001_ADC, &data);
+		mutex_unlock(&st->lock);
+		if (ret < 0)
+			return ret;
+
+		*val = data;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->vref_mv;
+		*val2 = 10;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info max14001_info = {
+	.read_raw = max14001_read_raw,
+};
+
+static const struct iio_chan_spec max14001_channels[] = {
+	{
+		.type = IIO_VOLTAGE,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+	}
+};
+
+static void max14001_regulator_disable(void *data)
+{
+	struct regulator *reg = data;
+
+	regulator_disable(reg);
+}
+
+static int max14001_init(struct max14001_state *st)
+{
+	int ret;
+
+	/* Enable SPI Registers Write */
+	ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN);
+	if (ret)
+		return ret;
+
+	/*
+	 * Reads all registers and writes the values back to their appropriate
+	 * verification registers to clear the Memory Validation fault.
+	 */
+	ret = max14001_write_verification_reg(st, MAX14001_FLTEN);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_THL);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_THU);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_INRR);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_INRT);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_INRP);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_CFG);
+	if (ret)
+		return ret;
+
+	ret = max14001_write_verification_reg(st, MAX14001_ENBL);
+	if (ret)
+		return ret;
+
+	/* Disable SPI Registers Write */
+	return max14001_write(st, MAX14001_WEN, 0);
+}
+
+static int max14001_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct max14001_state *st;
+	struct regulator *vref;
+	struct device *dev = &spi->dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+
+	indio_dev->name = "max14001";
+	indio_dev->info = &max14001_info;
+	indio_dev->channels = max14001_channels;
+	indio_dev->num_channels = ARRAY_SIZE(max14001_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = max14001_init(st);
+	if (ret)
+		return ret;
+
+	vref = devm_regulator_get_optional(dev, "vref");
+	if (IS_ERR(vref)) {
+		if (PTR_ERR(vref) != -ENODEV)
+			return dev_err_probe(dev, PTR_ERR(vref),
+					     "Failed to get vref regulator");
+
+		/* internal reference */
+		st->vref_mv = 1250;
+	} else {
+		ret = regulator_enable(vref);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					"Failed to enable vref regulators\n");
+
+		ret = devm_add_action_or_reset(dev, max14001_regulator_disable,
+					       vref);
+		if (ret)
+			return ret;
+
+		/* select external voltage reference source for the ADC */
+		ret = max14001_reg_update(st, MAX14001_CFG,
+					  MAX14001_CFG_EXRF, 1);
+
+		ret = regulator_get_voltage(vref);
+		if (ret < 0)
+			return dev_err_probe(dev, ret,
+					     "Failed to get vref\n");
+
+		st->vref_mv = ret / 1000;
+	}
+
+	mutex_init(&st->lock);
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id max14001_of_match[] = {
+	{ .compatible = "adi,max14001" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max14001_of_match);
+
+static struct spi_driver max14001_driver = {
+	.driver = {
+		.name = "max14001",
+		.of_match_table = max14001_of_match,
+	},
+	.probe = max14001_probe,
+};
+module_spi_driver(max14001_driver);
+
+MODULE_AUTHOR("Kim Seer Paller");
+MODULE_DESCRIPTION("MAX14001 ADC driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1

Re: [PATCH v4 1/2] dt-bindings:iio:adc: add max14001

[Rob Herring]

On Tue, 13 Jun 2023 13:46:00 +0800, Kim Seer Paller wrote:
> The MAX14001 is a configurable, isolated 10-bit ADC for multi-range
> binary inputs.
> 
> Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
> V3 -> V4: Added space between prefixes in commit description.
> 
>  .../bindings/iio/adc/adi,max14001.yaml        | 54 +++++++++++++++++++
>  MAINTAINERS                                   |  7 +++
>  2 files changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/pinctrl/qcom,pmic-mpp.yaml: $defs:qcom-pmic-mpp-state:properties:qcom,paired: [{'description': 'Indicates that the pin should be operating in paired mode.'}] is not of type 'object', 'boolean'
	from schema $id: http://devicetree.org/meta-schemas/core.yaml#

doc reference errors (make refcheckdocs):
MAINTAINERS: Documentation/devicetree/bindings/iio/dac/adi,max14001.yaml

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20230613054601.31566-1-kimseer.paller@analog.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v4 2/2] iio: adc: max14001: New driver

[Andy Shevchenko]

On Tue, Jun 13, 2023 at 8:46 AM Kim Seer Paller
<kimseer.paller@analog.com> wrote:
>
> The MAX14001 is a configurable, isolated 10-bit ADC for multi-range
> binary inputs.

...

> +struct max14001_state {
> +       struct spi_device       *spi;
> +       /*
> +        * lock protect agains multiple concurrent accesses, RMW sequence, and

against

> +        * SPI transfer
> +        */
> +       struct mutex            lock;
> +       int                     vref_mv;
> +       /*
> +        * DMA (thus cache coherency maintenance) requires the
> +        * transfer buffers to live in their own cache lines.
> +        */
> +       __be16                  spi_tx_buffer __aligned(IIO_DMA_MINALIGN);
> +       __be16                  spi_rx_buffer;
> +};
> +
> +static int max14001_read(void *context, unsigned int reg_addr, unsigned int *data)
> +{
> +       struct max14001_state *st = context;
> +       int ret;
> +
> +       struct spi_transfer xfers[] = {
> +               {
> +                       .tx_buf = &st->spi_tx_buffer,
> +                       .len = 2,

sizeof()

> +                       .cs_change = 1,
> +               }, {
> +                       .rx_buf = &st->spi_rx_buffer,
> +                       .len = 2,

sizeof()

> +               },
> +       };
> +
> +       st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK,
> +                                                               reg_addr)));
> +
> +       ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
> +       if (ret)
> +               return ret;
> +
> +       *data = bitrev16(be16_to_cpu(st->spi_rx_buffer)) & MAX14001_DATA_MASK;
> +
> +       return 0;
> +}

...

> +static const struct iio_chan_spec max14001_channels[] = {
> +       {
> +               .type = IIO_VOLTAGE,
> +               .channel = 0,

Is it required?

> +               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +                                     BIT(IIO_CHAN_INFO_SCALE),
> +       }
> +};

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 1/2] dt-bindings:iio:adc: add max14001

[Rob Herring]

On Tue, Jun 13, 2023 at 12:18:10AM -0600, Rob Herring wrote:
> 
> On Tue, 13 Jun 2023 13:46:00 +0800, Kim Seer Paller wrote:
> > The MAX14001 is a configurable, isolated 10-bit ADC for multi-range
> > binary inputs.
> > 
> > Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
> > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> > ---
> > V3 -> V4: Added space between prefixes in commit description.
> > 
> >  .../bindings/iio/adc/adi,max14001.yaml        | 54 +++++++++++++++++++
> >  MAINTAINERS                                   |  7 +++
> >  2 files changed, 61 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
> > 
> 
> My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
> on your patch (DT_CHECKER_FLAGS is new in v5.13):
> 
> yamllint warnings/errors:
> 
> dtschema/dtc warnings/errors:
> /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/pinctrl/qcom,pmic-mpp.yaml: $defs:qcom-pmic-mpp-state:properties:qcom,paired: [{'description': 'Indicates that the pin should be operating in paired mode.'}] is not of type 'object', 'boolean'
> 	from schema $id: http://devicetree.org/meta-schemas/core.yaml#

Unrelated, this can be ignored.

Rob